The present invention relates to a roller assembly fitting device for use in a roller blind of the type having a retractable pivot to set up the roller assembly in a mounting bracket.
The roller blind has a roller assembly supported by a pair of mounting brackets, the assembly including a hollow roller, a screen wound on the hollow roller, and a fitting device disposed at one end of the hollow roller. The device comprises an end sleeve removably secured to the hollow roller, a pivot retractably mounted in the sleeve, and a coil spring mounted in the sleeve to extrude the forward end portion of the pivot out of the sleeve into a bore in the bracket. The roller assembly is supported by the brackets, when the pivot has the forward end portion thereof inserted in the bracket by the coil spring which is not contracted. On the other hand, the roller assembly is passable between the opposite brackets while the coil spring is contracted to retract the pivot from the bracket.
The known device has no provision for locking the axial movement of the pivot, therefore permitting the pivot to retract when a thrust acts against the coil spring. Such a thrust sometimes occurs in the case where the roller blind is roughly operated or shaken by wind. This leads to an accident where the roller assembly suddenly drops down from the bracket to damage persons and articles under the blind.
It is the primary object of the invention to provide a roller assembly fitting device for use in a roller blind in which a pivot is selectively locked after the roller assembly is set up in the permanent position, thereby preventing the roller assembly from falling down.
To this end, a roller assembly fitting device in accordance with the invention includes a roller-end sleeve removably secured to a hollow roller on which a screen is wound, a guide sleeve coaxially mounted in the roller-end sleeve, the guide sleeve being rotatable between first and second angular positions in the roller-end sleeve, a pivot passing through the respective center bores in the roller-end and guide sleeves and being formed on the periphery with an annular step, axial and peripheral grooves, and a coil spring interposed between the bottom of the guide sleeve and the step of the pivot to bias them in the opposite directions. The guide sleeve has an inner radial projection for selective fitting engagement with the axial and peripheral grooves. The inner radial projection is in the axial groove to permit the axial movement of the pivot when the guide sleeve is in the first angular position and shifts in the peripheral groove to lock the axial movement of the pivot when the guide sleeve rotates to the second angular position.
The guide sleeve has a flange in the form of a handle pressed to a flange portion of the roller-end sleeve, the guide and roller-end flanges having their axial recess and projection coupled with each other. The recess is so cambered to put the projection either in one side of the recess in which the guide sleeve is in the first angular position or in the other side in which the guide sleeve is in the second angular position. The device has a stopper integrally formed in the pivot. The stopper is hook-shaped so as to be erected from the rear end portion of the pivot for abutting engagement with the bottom of the roller-end sleeve, thereby preventing the excessive extrusion of the pivot.
The advantages offered by the invention are mainly that the roller assembly never drops down even if the roller blind is roughly operated or shaken by wind. Damage to persons, articles, and the roller assembly itself is avoided. All in all, there is no danger under the blind.